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  • Author or Editor: Zejun Zhang x
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Abstract

The breeding of most high-altitude birds remains poorly known. We studied the breeding ecology of Kessler’s thrush (Turdus kessleri) and documented reproductive information throughout the nestling periods in the western Sichuan plateau. The data included natural nest sites, nest components, nest size, egg-laying dates, egg morphology, egg size, clutch size, egg incubation, nestling brooding and feeding, nestling morphology and growth, and reproductive outcome. The study found that T. kessleri used the old nest to breed. As the nestling grew, the female’s nestling brooding time decreased, and the feeding frequency of parent birds increased at first and then decreased. The frequency of clearing feces was positively correlated with the feeding frequency. The difference in the feeding frequency of both parents may be attributed to their division of labor, with a distinct difference between their investments. The parent birds’ cost of reproduction per nestling varies from one breeding period to the next. Predation by natural enemies is the main factor leading to reproductive failure in T. kessleri. This suite of life-history and behavioral strategies enables fledgling T. kessleri to cope with the harsh environments of mountains at higher altitudes.

In: Animal Biology

For any endangered species, our understanding of the spatial variability in its diet across its distribution range, can be important for its conservation. This study focuses on the feeding habitat of the giant panda. For one full year, we surveyed seasonal foraging behaviors of giant pandas (Ailuropoda melanoleuca) in Foping Nature Reserve, China. The results indicated that giant pandas mainly foraged on new shoots of Bashania fargesii and Fargesia qinlingensis in spring and summer, and leaves constituted the major part of their diet in autumn and winter. Stems only marginally occurred in their diet in late winter and early spring. The general pattern in diet composition of giant pandas across mountains reflected the combined consequence of nutrition quality and food availability. Factors affecting foraging-site selection by giant pandas differed across seasons. In spring, they preferred foraging sites closer to trails, with new shoots of B. fargesii higher in basal diameter and less affected by worms. In summer, they foraged at sites with higher density of new shoots and perennial bamboos. Besides overstorey canopy, slope and distance to trails were the other two factors affecting their foraging-site selection in autumn. Temporal variation in diet composition and foraging-site selection exhibited by giant pandas perhaps reflected behaviorally adaptive strategies to changing environmental factors, helping to maximize their energy intake for successful survival and reproduction. Our results, for the first time, support the hypothesized negative effect of some worms on foraging-site selection by giant pandas due to their ingestion of new shoots in spring. Protecting of giant panda foraging sites in these areas where abundant young bamboo resource exist, strengthening management of human activities which can influence giant pandas forage to improve forage habitat quality and widely implementing actions of biological worm pest control during the period when shoot sprouts are eaten can potentially have important implications for habitat conservation for this species.

In: Animal Biology

Vocal signals are a common communication tool used to recognize different individuals, advertise fertile phases or discriminate amongst potential mates. Therefore, a thorough understanding of vocal repertoires forms the basis for investigating the role of acoustic signaling in the sexual and social behavior of any animal. Red pandas (Ailurus fulgens) are classified as a vulnerable species and have declined by as much as 40% over the past 50 years in China. Adult red pandas are known to call frequently during mating and aggressive encounters; however, no quantitative description of their vocalizations has been attempted. Here, the vocal repertoire of captive red pandas was investigated. Acoustical and statistical analyses indicated seven vocalization types during the breeding season: “growl”, “bark”, “squeal”, “bleat”, “hoot”, “grunt” and “twitter”; the spectrogram for each vocalization type was extracted. The type of vocalizations produced varied with behavioral state and implies different functional contexts. Future studies are needed to uncover the functions of red panda vocalizations in individual recognition, sexual selection and social interaction.

In: Animal Biology